Import 2.3.25pre1

[davej-history.git] / net / appletalk / ddp.c

/*
 *      DDP:    An implementation of the AppleTalk DDP protocol for
 *              Ethernet 'ELAP'.
 *
 *              Alan Cox  <Alan.Cox@linux.org>
 *
 *              With more than a little assistance from
 *
 *              Wesley Craig <netatalk@umich.edu>
 *
 *      Fixes:
 *              Michael Callahan        :       Made routing work
 *              Wesley Craig            :       Fix probing to listen to a
 *                                              passed node id.
 *              Alan Cox                :       Added send/recvmsg support
 *              Alan Cox                :       Moved at. to protinfo in
 *                                              socket.
 *              Alan Cox                :       Added firewall hooks.
 *              Alan Cox                :       Supports new ARPHRD_LOOPBACK
 *              Christer Weinigel       :       Routing and /proc fixes.
 *              Bradford Johnson        :       LocalTalk.
 *              Tom Dyas                :       Module support.
 *              Alan Cox                :       Hooks for PPP (based on the
 *                                              LocalTalk hook).
 *              Alan Cox                :       Posix bits
 *              Alan Cox/Mike Freeman   :       Possible fix to NBP problems
 *              Bradford Johnson        :       IP-over-DDP (experimental)
 *              Jay Schulist            :       Moved IP-over-DDP to its own
 *                                              driver file. (ipddp.c & ipddp.h)
 *              Jay Schulist            :       Made work as module with 
 *                                              AppleTalk drivers, cleaned it.
 *              Rob Newberry            :       Added proxy AARP and AARP proc fs, 
 *                                              moved probing to AARP module.
 *              Adrian Sun/ 
 *              Michael Zuelsdorff      :       fix for net.0 packets. don't 
 *                                              allow illegal ether/tokentalk
 *                                              port assignment. we lose a 
 *                                              valid localtalk port as a 
 *                                              result.
 *              
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 * 
 */

#include <linux/config.h>
#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/route.h>
#include <linux/inet.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/termios.h>      /* For TIOCOUTQ/INQ */
#include <net/datalink.h>
#include <net/p8022.h>
#include <net/psnap.h>
#include <net/sock.h>
#include <linux/ip.h>
#include <net/route.h>
#include <linux/atalk.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>


#ifdef CONFIG_PROC_FS
extern void aarp_register_proc_fs(void);
extern void aarp_unregister_proc_fs(void);
#endif

extern void aarp_probe_network(struct atalk_iface *atif);
extern int  aarp_proxy_probe_network(struct atalk_iface *atif, struct at_addr *sa);
extern void aarp_proxy_remove(struct net_device *dev, struct at_addr *sa);


#undef APPLETALK_DEBUG

#ifdef APPLETALK_DEBUG
#define DPRINT(x)               print(x)
#else
#define DPRINT(x)
#endif /* APPLETALK_DEBUG */

#ifdef CONFIG_SYSCTL
extern inline void atalk_register_sysctl(void);
extern inline void atalk_unregister_sysctl(void);
#endif /* CONFIG_SYSCTL */

struct datalink_proto *ddp_dl, *aarp_dl;
static struct proto_ops atalk_dgram_ops;

#define min(a,b)        (((a)<(b))?(a):(b))

/**************************************************************************\
*                                                                          *
* Handlers for the socket list.                                            *
*                                                                          *
\**************************************************************************/

static struct sock *atalk_socket_list = NULL;

/*
 * Note: Sockets may not be removed _during_ an interrupt or inet_bh
 * handler using this technique. They can be added although we do not
 * use this facility.
 */

extern inline void atalk_remove_socket(struct sock *sk)
{
        sklist_remove_socket(&atalk_socket_list,sk);
}

extern inline void atalk_insert_socket(struct sock *sk)
{
        sklist_insert_socket(&atalk_socket_list,sk);
}

static struct sock *atalk_search_socket(struct sockaddr_at *to, struct atalk_iface *atif)
{
        struct sock *s;

        for(s = atalk_socket_list; s != NULL; s = s->next)
        {
                if(to->sat_port != s->protinfo.af_at.src_port)
                {
                        continue;
                }

                if(to->sat_addr.s_net == ATADDR_ANYNET
                        && to->sat_addr.s_node == ATADDR_BCAST
                        && s->protinfo.af_at.src_net == atif->address.s_net)
                {
                        break;
                }

                if(to->sat_addr.s_net == s->protinfo.af_at.src_net
                        && (to->sat_addr.s_node == s->protinfo.af_at.src_node
                        || to->sat_addr.s_node == ATADDR_BCAST
                        || to->sat_addr.s_node == ATADDR_ANYNODE))
                {
                        break;
                }

                /* XXXX.0 -- we got a request for this router. make sure
                 * that the node is appropriately set. */
                if (to->sat_addr.s_node == ATADDR_ANYNODE &&
                    to->sat_addr.s_net != ATADDR_ANYNET &&
                    atif->address.s_node == s->protinfo.af_at.src_node) {
                        to->sat_addr.s_node = atif->address.s_node;
                        break; 
                }
        }

        return (s);
}

/*
 * Find a socket in the list.
 */
static struct sock *atalk_find_socket(struct sockaddr_at *sat)
{
        struct sock *s;

        for(s = atalk_socket_list; s != NULL; s = s->next)
        {
                if(s->protinfo.af_at.src_net != sat->sat_addr.s_net)
                {
                        continue;
                }

                if(s->protinfo.af_at.src_node != sat->sat_addr.s_node)
                {
                        continue;
                }

                if(s->protinfo.af_at.src_port != sat->sat_port)
                {
                        continue;
                }

                break;
        }

        return (s);
}

extern inline void atalk_destroy_socket(struct sock *sk)
{
        sklist_destroy_socket(&atalk_socket_list, sk);
        MOD_DEC_USE_COUNT;
}

/*
 * Called from proc fs
 */
int atalk_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
{
        struct sock *s;
        int len=0;
        off_t pos=0;
        off_t begin=0;

        /*
         * Output the AppleTalk data for the /proc filesystem.
         */

        len += sprintf(buffer,"Type local_addr  remote_addr tx_queue rx_queue st uid\n");
        for(s = atalk_socket_list; s != NULL; s = s->next)
        {
                len += sprintf(buffer+len,"%02X   ", s->type);
                len += sprintf(buffer+len,"%04X:%02X:%02X  ",
                        ntohs(s->protinfo.af_at.src_net),
                        s->protinfo.af_at.src_node,
                        s->protinfo.af_at.src_port);
                len += sprintf(buffer+len,"%04X:%02X:%02X  ",
                        ntohs(s->protinfo.af_at.dest_net),
                        s->protinfo.af_at.dest_node,
                        s->protinfo.af_at.dest_port);
                len += sprintf(buffer+len,"%08X:%08X ",
                        atomic_read(&s->wmem_alloc),
                        atomic_read(&s->rmem_alloc));
                len += sprintf(buffer+len,"%02X %d\n", s->state, 
                        SOCK_INODE(s->socket)->i_uid);

                /* Are we still dumping unwanted data then discard the record */
                pos = begin + len;

                if(pos < offset)
                {
                        len = 0;        /* Keep dumping into the buffer start */
                        begin = pos;
                }
                if(pos > offset + length)       /* We have dumped enough */
                        break;
        }

        /* The data in question runs from begin to begin+len */
        *start = buffer + (offset - begin);     /* Start of wanted data */
        len -= (offset - begin);   /* Remove unwanted header data from length */
        if(len > length)
                len = length;      /* Remove unwanted tail data from length */

        return (len);
}

/**************************************************************************\
*                                                                          *
* Routing tables for the AppleTalk socket layer.                           *
*                                                                          *
\**************************************************************************/

static struct atalk_route *atalk_router_list = NULL;
static struct atalk_iface *atalk_iface_list  = NULL;
static struct atalk_route atrtr_default; /* For probing devices or in a routerless network */

/*
 * AppleTalk interface control
 */

/*
 * Drop a device. Doesn't drop any of its routes - that is the caller's
 * problem. Called when we down the interface or delete the address.
 */
static void atif_drop_device(struct net_device *dev)
{
        struct atalk_iface **iface = &atalk_iface_list;
        struct atalk_iface *tmp;

        while((tmp = *iface) != NULL)
        {
                if(tmp->dev == dev)
                {
                        *iface = tmp->next;
                        kfree_s(tmp, sizeof(struct atalk_iface));
                        dev->atalk_ptr=NULL;
                        MOD_DEC_USE_COUNT;
                }
                else
                        iface = &tmp->next;
        }

}

static struct atalk_iface *atif_add_device(struct net_device *dev, struct at_addr *sa)
{
        struct atalk_iface *iface = (struct atalk_iface *)
                kmalloc(sizeof(*iface), GFP_KERNEL);
        unsigned long flags;

        if(iface==NULL)
                return (NULL);

        iface->dev=dev;
        dev->atalk_ptr=iface;
        iface->address= *sa;
        iface->status=0;
        save_flags(flags);
        cli();
        iface->next=atalk_iface_list;
        atalk_iface_list=iface;
        restore_flags(flags);

        MOD_INC_USE_COUNT;

        return (iface);
}


/*
 * Perform phase 2 AARP probing on our tentative address.
 */
static int atif_probe_device(struct atalk_iface *atif)
{
        int netrange=ntohs(atif->nets.nr_lastnet)-ntohs(atif->nets.nr_firstnet)+1;
        int probe_net=ntohs(atif->address.s_net);
        int probe_node=atif->address.s_node;
        int netct, nodect;

        /*
         * Offset the network we start probing with.
         */

        if(probe_net == ATADDR_ANYNET)
        {
                if(!netrange)
                        probe_net = ntohs(atif->nets.nr_firstnet);
                else
                        probe_net = ntohs(atif->nets.nr_firstnet) + (jiffies%netrange);
        }

        if(probe_node == ATADDR_ANYNODE)
                probe_node = jiffies&0xFF;

        /*
         * Scan the networks.
         */
        atif->status |= ATIF_PROBE;
        for(netct = 0; netct <= netrange; netct++)
        {
                /*
                 * Sweep the available nodes from a given start.
                 */

                atif->address.s_net = htons(probe_net);
                for(nodect = 0; nodect < 256; nodect++)
                {
                        atif->address.s_node = ((nodect+probe_node) & 0xFF);
                        if(atif->address.s_node > 0 && atif->address.s_node<254)
                        {
                                /*
                                 * Probe a proposed address.
                                 */
                                aarp_probe_network(atif);

                                if(!(atif->status & ATIF_PROBE_FAIL)) {
                                        atif->status &= ~ATIF_PROBE;
                                        return (0);
                                }
                        }
                        atif->status &= ~ATIF_PROBE_FAIL;
                }
                probe_net++;
                if(probe_net > ntohs(atif->nets.nr_lastnet))
                        probe_net = ntohs(atif->nets.nr_firstnet);
        }
        atif->status &= ~ATIF_PROBE;
        return (-EADDRINUSE);   /* Network is full... */
}


/*
 * Perform AARP probing for a proxy address
 */
static int atif_proxy_probe_device(struct atalk_iface *atif, struct at_addr* proxy_addr)
{
        int netrange=ntohs(atif->nets.nr_lastnet)-ntohs(atif->nets.nr_firstnet)+1;
        int probe_net=ntohs(atif->address.s_net);       // we probe the interface's network
        int probe_node=ATADDR_ANYNODE;                          // we'll take anything
        int netct, nodect;

        /*
         * Offset the network we start probing with.
         */

        if(probe_net == ATADDR_ANYNET)
        {
                if(!netrange)
                        probe_net = ntohs(atif->nets.nr_firstnet);
                else
                        probe_net = ntohs(atif->nets.nr_firstnet) + (jiffies%netrange);
        }

        if(probe_node == ATADDR_ANYNODE)
                probe_node = jiffies&0xFF;
                
        /*
         * Scan the networks.
         */

        for(netct = 0; netct <= netrange; netct++)
        {
                /*
                 * Sweep the available nodes from a given start.
                 */

                proxy_addr->s_net = htons(probe_net);
                for(nodect = 0; nodect < 256; nodect++)
                {
                        proxy_addr->s_node = ((nodect+probe_node) & 0xFF);
                        if((proxy_addr->s_node>0) && (proxy_addr->s_node<254))
                        {
                                /*
                                 * Tell AARP to probe a proposed address.
                                 */
                                int probe_result = aarp_proxy_probe_network(atif, proxy_addr);

                                if (probe_result == 0)
                                        return 0;
                                        
                                if (probe_result != -EADDRINUSE)
                                        return probe_result;
                        }
                }
                probe_net++;
                if(probe_net > ntohs(atif->nets.nr_lastnet))
                        probe_net = ntohs(atif->nets.nr_firstnet);
        }

        return (-EADDRINUSE);   /* Network is full... */
}


struct at_addr *atalk_find_dev_addr(struct net_device *dev)
{
        struct atalk_iface *iface=dev->atalk_ptr;

        if(iface)
                return (&iface->address);

        return (NULL);
}

static struct at_addr *atalk_find_primary(void)
{
        struct atalk_iface *iface;
        struct atalk_iface *fiface = NULL;

        /*
         * Return a point-to-point interface only if
         * there is no non-ptp interface available.
         */
        for(iface=atalk_iface_list; iface != NULL; iface=iface->next)
        {
                if(!fiface && !(iface->dev->flags & IFF_LOOPBACK))
                        fiface=iface;
                if(!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)))
                        return (&iface->address);
        }

        if(fiface)
                return (&fiface->address);
        if(atalk_iface_list != NULL)
                return (&atalk_iface_list->address);
        else
                return (NULL);
}

/*
 * Find a match for 'any network' - ie any of our interfaces with that
 * node number will do just nicely.
 */
static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
{
        struct atalk_iface *iface=dev->atalk_ptr;

        if(iface==NULL || (iface->status & ATIF_PROBE))
                return (NULL);
        if(node == ATADDR_BCAST || iface->address.s_node == node
                || node == ATADDR_ANYNODE)
                return (iface);

        return (NULL);
}

/*
 * Find a match for a specific network:node pair
 */
static struct atalk_iface *atalk_find_interface(int net, int node)
{
        struct atalk_iface *iface;

        for(iface=atalk_iface_list; iface != NULL; iface=iface->next)
        {
                if((node==ATADDR_BCAST || node==ATADDR_ANYNODE 
                        || iface->address.s_node==node)
                        && iface->address.s_net==net 
                        && !(iface->status & ATIF_PROBE))
                        return (iface);

                /* XXXX.0 -- net.0 returns the iface associated with net */
                if ((node==ATADDR_ANYNODE) && (net != ATADDR_ANYNET) &&
                    (ntohs(iface->nets.nr_firstnet) <= ntohs(net)) &&
                    (ntohs(net) <= ntohs(iface->nets.nr_lastnet)))
                        return (iface);
        }

        return (NULL);
}


/*
 * Find a route for an AppleTalk packet. This ought to get cached in
 * the socket (later on...). We know about host routes and the fact
 * that a route must be direct to broadcast.
 */
static struct atalk_route *atrtr_find(struct at_addr *target)
{
        /*
         * we must search through all routes unless we find a 
         * host route, because some host routes might overlap
         * network routes
         */
        struct atalk_route *r;
        struct atalk_route *net_route = NULL;
        
        for(r=atalk_router_list; r != NULL; r=r->next)
        {
                if(!(r->flags & RTF_UP))
                        continue;
                if(r->target.s_net == target->s_net)
                {
                        if (r->flags & RTF_HOST)
                        {
                                /*
                                 * if this host route is for the target,
                                 * the we're done
                                 */
                                if (r->target.s_node == target->s_node)
                                        return (r);
                        }
                        else
                        {
                                /*
                                 * this route will work if there isn't a
                                 * direct host route, so cache it
                                 */
                                net_route = r;
                        }
                }
        }
        
        /* 
         * if we found a network route but not a direct host
         * route, then return it
         */
        if (net_route != NULL)
                return (net_route);

        if(atrtr_default.dev)
                return (&atrtr_default);

        return (NULL);
}


/*
 * Given an AppleTalk network, find the device to use. This can be
 * a simple lookup.
 */
struct net_device *atrtr_get_dev(struct at_addr *sa)
{
        struct atalk_route *atr=atrtr_find(sa);

        if(atr == NULL)
                return (NULL);
        else
                return (atr->dev);
}

/*
 * Set up a default router.
 */
static void atrtr_set_default(struct net_device *dev)
{
        atrtr_default.dev = dev;
        atrtr_default.flags = RTF_UP;
        atrtr_default.gateway.s_net = htons(0);
        atrtr_default.gateway.s_node = 0;
}

/*
 * Add a router. Basically make sure it looks valid and stuff the
 * entry in the list. While it uses netranges we always set them to one
 * entry to work like netatalk.
 */
static int atrtr_create(struct rtentry *r, struct net_device *devhint)
{
        struct sockaddr_at *ta=(struct sockaddr_at *)&r->rt_dst;
        struct sockaddr_at *ga=(struct sockaddr_at *)&r->rt_gateway;
        struct atalk_route *rt;
        struct atalk_iface *iface, *riface;
        unsigned long flags;

        save_flags(flags);

        /*
         * Fixme: Raise/Lower a routing change semaphore for these
         * operations.
         */

        /*
         * Validate the request
         */
        if(ta->sat_family != AF_APPLETALK)
                return (-EINVAL);
        if(devhint == NULL && ga->sat_family != AF_APPLETALK)
                return (-EINVAL);

        /*
         * Now walk the routing table and make our decisions.
         */
        for(rt=atalk_router_list; rt!=NULL; rt=rt->next)
        {
                if(r->rt_flags != rt->flags)
                        continue;

                if(ta->sat_addr.s_net == rt->target.s_net)
                {
                        if(!(rt->flags & RTF_HOST))
                                break;
                        if(ta->sat_addr.s_node == rt->target.s_node)
                                break;
                }
        }

        if(devhint == NULL)
        {
                for(riface = NULL, iface = atalk_iface_list; iface; iface = iface->next)
                {
                        if(riface == NULL && ntohs(ga->sat_addr.s_net) >= ntohs(iface->nets.nr_firstnet) &&
                                ntohs(ga->sat_addr.s_net) <= ntohs(iface->nets.nr_lastnet))
                        {
                                riface = iface;
                        }
                        if(ga->sat_addr.s_net == iface->address.s_net 
                                && ga->sat_addr.s_node == iface->address.s_node)
                                riface = iface;
                }

                if(riface == NULL)
                        return (-ENETUNREACH);
                devhint = riface->dev;
        }

        if(rt == NULL)
        {
                rt = (struct atalk_route *)kmalloc(sizeof(struct atalk_route), GFP_KERNEL);
                if(rt == NULL)
                        return (-ENOBUFS);
                cli();
                rt->next = atalk_router_list;
                atalk_router_list = rt;
        }

        /*
         * Fill in the routing entry.
         */
        rt->target  = ta->sat_addr;
        rt->dev     = devhint;
        rt->flags   = r->rt_flags;
        rt->gateway = ga->sat_addr;

        restore_flags(flags);

        return (0);
}

/*
 * Delete a route. Find it and discard it.
 */
static int atrtr_delete( struct at_addr *addr )
{
        struct atalk_route **r = &atalk_router_list;
        struct atalk_route *tmp;

        while((tmp = *r) != NULL)
        {
                if(tmp->target.s_net == addr->s_net
                        && (!(tmp->flags&RTF_GATEWAY)
                        || tmp->target.s_node == addr->s_node))
                {
                        *r = tmp->next;
                        kfree_s(tmp, sizeof(struct atalk_route));
                        return (0);
                }
                r = &tmp->next;
        }

        return (-ENOENT);
}

/*
 * Called when a device is downed. Just throw away any routes
 * via it.
 */
void atrtr_device_down(struct net_device *dev)
{
        struct atalk_route **r = &atalk_router_list;
        struct atalk_route *tmp;

        while((tmp = *r) != NULL)
        {
                if(tmp->dev == dev)
                {
                        *r = tmp->next;
                        kfree_s(tmp, sizeof(struct atalk_route));
                }
                else
                        r = &tmp->next;
        }

        if(atrtr_default.dev == dev)
                atrtr_set_default(NULL);
}

/*
 * Actually down the interface.
 */
static inline void atalk_dev_down(struct net_device *dev)
{
        atrtr_device_down(dev); /* Remove all routes for the device */
        aarp_device_down(dev);  /* Remove AARP entries for the device */
        atif_drop_device(dev);  /* Remove the device */
}

/*
 * A device event has occurred. Watch for devices going down and
 * delete our use of them (iface and route).
 */
static int ddp_device_event(struct notifier_block *this, unsigned long event, void *ptr)
{
        if(event == NETDEV_DOWN)
        {
                /* Discard any use of this */
                atalk_dev_down((struct net_device *) ptr);
        }

        return (NOTIFY_DONE);
}

/*
 * ioctl calls. Shouldn't even need touching.
 */

/*
 * Device configuration ioctl calls.
 */
int atif_ioctl(int cmd, void *arg)
{
        struct ifreq atreq;
        static char aarp_mcast[6] = {0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF};
        struct netrange *nr;
        struct sockaddr_at *sa;
        struct net_device *dev;
        struct atalk_iface *atif;
        int ct;
        int limit;
        struct rtentry rtdef;
        int     add_route;

        if(copy_from_user(&atreq,arg,sizeof(atreq)))
                return (-EFAULT);

        if((dev = __dev_get_by_name(atreq.ifr_name)) == NULL)
                return (-ENODEV);

        sa=(struct sockaddr_at*)&atreq.ifr_addr;
        atif=atalk_find_dev(dev);

        switch(cmd)
        {
                case SIOCSIFADDR:
                        if(!capable(CAP_NET_ADMIN))
                                return (-EPERM);
                        if(sa->sat_family != AF_APPLETALK)
                                return (-EINVAL);
                        if(dev->type != ARPHRD_ETHER
                                && dev->type != ARPHRD_LOOPBACK
                                && dev->type != ARPHRD_LOCALTLK
                                && dev->type != ARPHRD_PPP)
                                return (-EPROTONOSUPPORT);

                        nr=(struct netrange *)&sa->sat_zero[0];

                        add_route = 1;

                        /*
                         * if this is a point-to-point iface, and we already have an 
                         * iface for this AppleTalk address, then we should not add a route
                         */
                        if (dev->flags & IFF_POINTOPOINT && atalk_find_interface(sa->sat_addr.s_net, sa->sat_addr.s_node))
                        {
                                printk(KERN_DEBUG "AppleTalk: point-to-point interface added with existing address\n");
                                add_route = 0;
                        }
                        
                        /*
                         * Phase 1 is fine on LocalTalk but we don't do
                         * EtherTalk phase 1. Anyone wanting to add it go ahead.
                         */
                        if(dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
                                return (-EPROTONOSUPPORT);
                        if(sa->sat_addr.s_node == ATADDR_BCAST 
                                || sa->sat_addr.s_node == 254)
                                return (-EINVAL);
                        if(atif)
                        {
                                /*
                                 * Already setting address.
                                 */
                                if(atif->status&ATIF_PROBE)
                                        return (-EBUSY);

                                atif->address.s_net  = sa->sat_addr.s_net;
                                atif->address.s_node = sa->sat_addr.s_node;
                                atrtr_device_down(dev); /* Flush old routes */
                        }
                        else
                        {
                                atif=atif_add_device(dev, &sa->sat_addr);
                                if (atif == NULL)
                                        return (-ENOMEM);
                        }
                        atif->nets= *nr;

                        /*
                         * Check if the chosen address is used. If so we
                         * error and atalkd will try another.
                         */

                        if(!(dev->flags & IFF_LOOPBACK) && !(dev->flags & IFF_POINTOPOINT) && atif_probe_device(atif) < 0)
                        {
                                atif_drop_device(dev);
                                return (-EADDRINUSE);
                        }

                        /*
                         * Hey it worked - add the direct routes.
                         */

                        sa = (struct sockaddr_at *)&rtdef.rt_gateway;
                        sa->sat_family = AF_APPLETALK;
                        sa->sat_addr.s_net  = atif->address.s_net;
                        sa->sat_addr.s_node = atif->address.s_node;
                        sa = (struct sockaddr_at *)&rtdef.rt_dst;
                        rtdef.rt_flags = RTF_UP;
                        sa->sat_family = AF_APPLETALK;
                        sa->sat_addr.s_node = ATADDR_ANYNODE;
                        if((dev->flags & IFF_LOOPBACK) || (dev->flags & IFF_POINTOPOINT))
                                rtdef.rt_flags |= RTF_HOST;

                        /*
                         * Routerless initial state.
                         */
                        if(nr->nr_firstnet == htons(0)
                                && nr->nr_lastnet == htons(0xFFFE))
                        {
                                sa->sat_addr.s_net = atif->address.s_net;
                                atrtr_create(&rtdef, dev);
                                atrtr_set_default(dev);
                        }
                        else
                        {
                                limit = ntohs(nr->nr_lastnet);
                                if(limit - ntohs(nr->nr_firstnet) > 4096)
                                {
                                        printk(KERN_WARNING "Too many routes/iface.\n");
                                        return (-EINVAL);
                                }
                                if (add_route)
                                        for(ct=ntohs(nr->nr_firstnet);ct<=limit;ct++)
                                        {
                                                sa->sat_addr.s_net = htons(ct);
                                                atrtr_create(&rtdef, dev);
                                        }
                        }
                        dev_mc_add(dev, aarp_mcast, 6, 1);
                        return (0);

                case SIOCGIFADDR:
                        if(atif == NULL)
                                return (-EADDRNOTAVAIL);
                        ((struct sockaddr_at *)(&atreq.ifr_addr))->sat_family=AF_APPLETALK;
                        ((struct sockaddr_at *)(&atreq.ifr_addr))->sat_addr=atif->address;
                        break;

                case SIOCGIFBRDADDR:
                        if(atif == NULL)
                                return (-EADDRNOTAVAIL);
                        ((struct sockaddr_at *)(&atreq.ifr_addr))->sat_family=AF_APPLETALK;
                        ((struct sockaddr_at *)(&atreq.ifr_addr))->sat_addr.s_net=atif->address.s_net;
                        ((struct sockaddr_at *)(&atreq.ifr_addr))->sat_addr.s_node=ATADDR_BCAST;
                        break;

                case SIOCATALKDIFADDR:
                case SIOCDIFADDR:
                        if(!capable(CAP_NET_ADMIN))
                                return (-EPERM);
                        if(sa->sat_family != AF_APPLETALK)
                                return (-EINVAL);
                        atalk_dev_down(dev);
                        break;                  

                case SIOCSARP:
                        if(!capable(CAP_NET_ADMIN))
                                return (-EPERM);
                        if(sa->sat_family != AF_APPLETALK)
                                return (-EINVAL);
                        if (atif == NULL)
                                return (-EADDRNOTAVAIL);

                        /*
                         * for now, we only support proxy AARP on ELAP;
                         * we should be able to do it for LocalTalk, too.
                         */
                        if(dev->type != ARPHRD_ETHER)
                                return (-EPROTONOSUPPORT);

                        /*
                         * atif points to the current interface on this network;
                         * we aren't concerned about its current status (at least for now),
                         * but it has all the settings about the network we're going
                         * to probe.  consequently, it must exist.
                         */
                        if (!atif)
                                return (-EADDRNOTAVAIL);

                        nr=(struct netrange *)&(atif->nets);
                        /*
                         * Phase 1 is fine on Localtalk but we don't do
                         * Ethertalk phase 1. Anyone wanting to add it go ahead.
                         */
                        if(dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
                                return (-EPROTONOSUPPORT);

                        if(sa->sat_addr.s_node == ATADDR_BCAST
                                || sa->sat_addr.s_node == 254)
                                return (-EINVAL);

                        /*
                         * Check if the chosen address is used. If so we
                         * error and ATCP will try another.
                         */
                        if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
                                return (-EADDRINUSE);
                        
                       /*
                         * We now have an address on the local network, and the AARP
                         * code will defend it for us until we take it down.
                         * We don't set up any routes right now, because ATCP will
                         * install them manually via SIOCADDRT.
                         */
                        break;

                case SIOCDARP:
                        if(!capable(CAP_NET_ADMIN))
                                return (-EPERM);
                        if(sa->sat_family != AF_APPLETALK)
                                return (-EINVAL);
                        if (atif == NULL)
                                return (-EADDRNOTAVAIL);

                        /*
                         * give to aarp module to remove proxy entry
                         */
                        aarp_proxy_remove(atif->dev, &(sa->sat_addr));

                        return (0);
        }

        if(copy_to_user(arg, &atreq, sizeof(atreq)))
                return (-EFAULT);

        return (0);
}

/*
 * Routing ioctl() calls
 */
static int atrtr_ioctl(unsigned int cmd, void *arg)
{
        struct rtentry rt;
        struct net_device *dev = NULL;

        if(copy_from_user(&rt, arg, sizeof(rt)))
                return (-EFAULT);

        switch(cmd)
        {
                case SIOCDELRT:
                        if(rt.rt_dst.sa_family != AF_APPLETALK)
                                return (-EINVAL);
                        return (atrtr_delete(&((struct sockaddr_at *)&rt.rt_dst)->sat_addr));

                case SIOCADDRT:
                        /* FIX ME: the name of the device is still in user space, isn't it? */
                        if (rt.rt_dev != NULL)
                                if ((dev = __dev_get_by_name(rt.rt_dev)) == NULL)
                                        return -(ENODEV);
                        
                        return (atrtr_create(&rt, dev));

                default:
                        return (-EINVAL);
        }
}

/* Called from proc fs - just make it print the ifaces neatly */

int atalk_if_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
{
        struct atalk_iface *iface;
        int len=0;
        off_t pos=0;
        off_t begin=0;

        len += sprintf(buffer,"Interface          Address   Networks   Status\n");
        for(iface = atalk_iface_list; iface != NULL; iface = iface->next)
        {
                len += sprintf(buffer+len,"%-16s %04X:%02X  %04X-%04X  %d\n",
                        iface->dev->name, ntohs(iface->address.s_net),
                        iface->address.s_node, ntohs(iface->nets.nr_firstnet),
                        ntohs(iface->nets.nr_lastnet), iface->status);
                pos = begin + len;
                if(pos < offset)
                {
                        len   = 0;
                        begin = pos;
                }
                if(pos > offset + length)
                        break;
        }
        *start = buffer + (offset - begin);
        len -= (offset - begin);
        if(len > length)
                len = length;

        return (len);
}

/* Called from proc fs - just make it print the routes neatly */

int atalk_rt_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
{
        struct atalk_route *rt;
        int len=0;
        off_t pos=0;
        off_t begin=0;

        len += sprintf(buffer,"Target        Router  Flags Dev\n");
        if(atrtr_default.dev)
        {
                rt = &atrtr_default;
                len += sprintf(buffer+len,"Default     %04X:%02X  %-4d  %s\n",
                        ntohs(rt->gateway.s_net), rt->gateway.s_node, rt->flags,
                        rt->dev->name);
        }

        for(rt = atalk_router_list; rt != NULL; rt = rt->next)
        {
                len += sprintf(buffer+len,"%04X:%02X     %04X:%02X  %-4d  %s\n",
                        ntohs(rt->target.s_net),rt->target.s_node,
                        ntohs(rt->gateway.s_net), rt->gateway.s_node, rt->flags,
                        rt->dev->name);
                pos = begin + len;
                if(pos < offset)
                {
                        len = 0;
                        begin = pos;
                }
                if(pos > offset + length)
                        break;
        }

        *start = buffer + (offset - begin);
        len -= (offset - begin);
        if(len > length)
                len = length;

        return (len);
}

/**************************************************************************\
*                                                                          *
* Handling for system calls applied via the various interfaces to an       *
* AppleTalk socket object.                                                 *
*                                                                          *
\**************************************************************************/

/*
 * Checksum: This is 'optional'. It's quite likely also a good
 * candidate for assembler hackery 8)
 */
unsigned short atalk_checksum(struct ddpehdr *ddp, int len)
{
        unsigned long sum=0;    /* Assume unsigned long is >16 bits */
        unsigned char *data=(unsigned char *)ddp;

        len  -= 4;              /* skip header 4 bytes */
        data += 4;

        /* This ought to be unwrapped neatly. I'll trust gcc for now */
        while(len--)
        {
                sum += *data;
                sum <<= 1;
                if(sum & 0x10000)
                {
                        sum++;
                        sum &= 0xFFFF;
                }
                data++;
        }

        if(sum)
                return htons((unsigned short)sum);

        return 0xFFFF;          /* Use 0xFFFF for 0. 0 itself means none */
}

/*
 * Create a socket. Initialise the socket, blank the addresses
 * set the state.
 */
static int atalk_create(struct socket *sock, int protocol)
{
        struct sock *sk;

        sk = sk_alloc(PF_APPLETALK, GFP_KERNEL, 1);
        if(sk == NULL)
                return (-ENOMEM);

        switch(sock->type)
        {
                /*
                 * We permit SOCK_DGRAM and RAW is an extension. It is
                 * trivial to do and gives you the full ELAP frame.
                 * Should be handy for CAP 8) 
                 */
                case SOCK_RAW:
                case SOCK_DGRAM:
                        sock->ops = &atalk_dgram_ops;
                        break;
                        
                case SOCK_STREAM:
                        /*
                         * TO DO: if you want to implement ADSP, here's the place to start
                         */
                        /*
                        sock->ops = &atalk_stream_ops;
                        break;
                        */
                default:
                        sk_free((void *)sk);
                        return (-ESOCKTNOSUPPORT);
        }

        MOD_INC_USE_COUNT;

        sock_init_data(sock,sk);

        sk->destruct = NULL;
        /* Checksums on by default */
        sk->zapped = 1;

        return (0);
}

/*
 * Free a socket. No work needed
 */
static int atalk_release(struct socket *sock)
{
        struct sock *sk=sock->sk;

        if(sk == NULL)
                return (0);

        if(!sk->dead)
                sk->state_change(sk);

        sk->dead = 1;
        sock->sk = NULL;
        atalk_destroy_socket(sk);

        return (0);
}

/*
 * Pick a source address if one is not given. Just return
 * an error if not supportable.
 */
static int atalk_pick_port(struct sockaddr_at *sat)
{
        for(sat->sat_port = ATPORT_RESERVED; sat->sat_port < ATPORT_LAST; sat->sat_port++)
        {
                if(atalk_find_socket(sat) == NULL)
                        return sat->sat_port;
        }

        return (-EBUSY);
}

static int atalk_autobind(struct sock *sk)
{
        struct at_addr *ap = atalk_find_primary();
        struct sockaddr_at sat;
        int n;

        if(ap == NULL || ap->s_net == htons(ATADDR_ANYNET))
                return (-EADDRNOTAVAIL);

        sk->protinfo.af_at.src_net  = sat.sat_addr.s_net  = ap->s_net;
        sk->protinfo.af_at.src_node = sat.sat_addr.s_node = ap->s_node;

        if((n = atalk_pick_port(&sat)) < 0)
                return (n);

        sk->protinfo.af_at.src_port = n;
        atalk_insert_socket(sk);
        sk->zapped = 0;

        return (0);
}

/*
 * Set the address 'our end' of the connection.
 */
static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
        struct sock *sk;
        struct sockaddr_at *addr=(struct sockaddr_at *)uaddr;

        sk = sock->sk;

        if(sk->zapped == 0)
                return (-EINVAL);

        if(addr_len != sizeof(struct sockaddr_at))
                return (-EINVAL);

        if(addr->sat_family != AF_APPLETALK)
                return (-EAFNOSUPPORT);

        if(addr->sat_addr.s_net == htons(ATADDR_ANYNET))
        {
                struct at_addr *ap=atalk_find_primary();

                if(ap == NULL)
                        return (-EADDRNOTAVAIL);

                sk->protinfo.af_at.src_net  = addr->sat_addr.s_net = ap->s_net;
                sk->protinfo.af_at.src_node = addr->sat_addr.s_node= ap->s_node;
        }
        else
        {
                if(atalk_find_interface(addr->sat_addr.s_net, addr->sat_addr.s_node) == NULL)
                        return (-EADDRNOTAVAIL);

                sk->protinfo.af_at.src_net  = addr->sat_addr.s_net;
                sk->protinfo.af_at.src_node = addr->sat_addr.s_node;
        }

        if(addr->sat_port == ATADDR_ANYPORT)
        {
                int n = atalk_pick_port(addr);
                if(n < 0)
                        return (n);

                sk->protinfo.af_at.src_port = addr->sat_port = n;
        }
        else
                sk->protinfo.af_at.src_port = addr->sat_port;

        if(atalk_find_socket(addr) != NULL)
                return (-EADDRINUSE);

        atalk_insert_socket(sk);
        sk->zapped = 0;

        return (0);
}

/*
 * Set the address we talk to.
 */
static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
        int addr_len, int flags)
{
        struct sock *sk=sock->sk;
        struct sockaddr_at *addr;

        sk->state   = TCP_CLOSE;
        sock->state = SS_UNCONNECTED;

        if(addr_len != sizeof(*addr))
                return (-EINVAL);
        addr = (struct sockaddr_at *)uaddr;

        if(addr->sat_family != AF_APPLETALK)
                return (-EAFNOSUPPORT);

        if(addr->sat_addr.s_node == ATADDR_BCAST && !sk->broadcast)
        {
#if 1   
                printk(KERN_WARNING "%s is broken and did not set SO_BROADCAST. It will break when 2.2 is released.\n",
                        current->comm);
#else
                return (-EACCES);
#endif                  
        }

        if(sk->zapped)
        {
                if(atalk_autobind(sk) < 0)
                        return (-EBUSY);
        }

        if(atrtr_get_dev(&addr->sat_addr) == NULL)
                return (-ENETUNREACH);

        sk->protinfo.af_at.dest_port = addr->sat_port;
        sk->protinfo.af_at.dest_net  = addr->sat_addr.s_net;
        sk->protinfo.af_at.dest_node = addr->sat_addr.s_node;

        sock->state = SS_CONNECTED;
        sk->state   = TCP_ESTABLISHED;

        return (0);
}


/*
 * Find the name of an AppleTalk socket. Just copy the right
 * fields into the sockaddr.
 */
static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
        int *uaddr_len, int peer)
{
        struct sockaddr_at sat;
        struct sock *sk;

        sk = sock->sk;
        if(sk->zapped)
        {
                if(atalk_autobind(sk) < 0)
                        return (-ENOBUFS);
        }

        *uaddr_len = sizeof(struct sockaddr_at);

        if(peer)
        {
                if(sk->state != TCP_ESTABLISHED)
                        return (-ENOTCONN);
                sat.sat_addr.s_net  = sk->protinfo.af_at.dest_net;
                sat.sat_addr.s_node = sk->protinfo.af_at.dest_node;
                sat.sat_port = sk->protinfo.af_at.dest_port;
        }
        else
        {
                sat.sat_addr.s_net  = sk->protinfo.af_at.src_net;
                sat.sat_addr.s_node = sk->protinfo.af_at.src_node;
                sat.sat_port = sk->protinfo.af_at.src_port;
        }

        sat.sat_family = AF_APPLETALK;
        memcpy(uaddr, &sat, sizeof(sat));

        return (0);
}

/*
 * Receive a packet (in skb) from device dev. This has come from the SNAP
 * decoder, and on entry skb->h.raw is the DDP header, skb->len is the DDP
 * header, skb->len is the DDP length. The physical headers have been
 * extracted. PPP should probably pass frames marked as for this layer.
 * [ie ARPHRD_ETHERTALK]
 */
static int atalk_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
{
        struct sock *sock;
        struct ddpehdr *ddp=(void *)skb->h.raw;
        struct atalk_iface *atif;
        struct sockaddr_at tosat;
        int origlen;
        struct ddpebits ddphv;

        /* Size check */
        if(skb->len < sizeof(*ddp))
        {
                kfree_skb(skb);
                return (0);
        }

        /*
         *      Fix up the length field [Ok this is horrible but otherwise
         *      I end up with unions of bit fields and messy bit field order
         *      compiler/endian dependencies..]
         *
         *      FIXME: This is a write to a shared object. Granted it
         *      happens to be safe BUT.. (Its safe as user space will not
         *      run until we put it back)
         */

        *((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));

        /*
         * Trim buffer in case of stray trailing data
         */

        origlen = skb->len;

        skb_trim(skb, min(skb->len, ddphv.deh_len));

        /*
         * Size check to see if ddp->deh_len was crap
         * (Otherwise we'll detonate most spectacularly
         * in the middle of recvmsg()).
         */
        if(skb->len < sizeof(*ddp))
        {
                kfree_skb(skb);
                return (0);
        }

        /*
         * Any checksums. Note we don't do htons() on this == is assumed to be
         * valid for net byte orders all over the networking code...
         */
        if(ddp->deh_sum && atalk_checksum(ddp, ddphv.deh_len) != ddp->deh_sum)
        {
                /* Not a valid AppleTalk frame - dustbin time */
                kfree_skb(skb);
                return (0);
        }

        /* Check the packet is aimed at us */

        if(ddp->deh_dnet == 0)  /* Net 0 is 'this network' */
                atif = atalk_find_anynet(ddp->deh_dnode, dev);
        else
                atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);

        /* 
         * Not ours, so we route the packet via the correct AppleTalk interface.
         */
        if(atif == NULL)
        {
                struct atalk_route *rt;
                struct at_addr ta;

                /*
                 * Don't route multicast, etc., packets, or packets
                 * sent to "this network" 
                 */
                if (skb->pkt_type != PACKET_HOST || ddp->deh_dnet == 0)
                {
                        /*
                         * FIX ME:
                         * Can it ever happen that a packet is from a PPP iface and needs to be broadcast onto the default network?
                         */
                        if (dev->type == ARPHRD_PPP)
                                printk(KERN_DEBUG "AppleTalk: didn't forward broadcast packet received from PPP iface\n");
                        
                        kfree_skb(skb);
                        return (0);
                }

                ta.s_net  = ddp->deh_dnet;
                ta.s_node = ddp->deh_dnode;

                /* Route the packet */
                rt = atrtr_find(&ta);
                if(rt == NULL || ddphv.deh_hops == DDP_MAXHOPS)
                {
                        kfree_skb(skb);
                        return (0);
                }
                ddphv.deh_hops++;

                /*
                 * Route goes through another gateway, so
                 * set the target to the gateway instead.
                 */
                if(rt->flags & RTF_GATEWAY)
                {
                        ta.s_net  = rt->gateway.s_net;
                        ta.s_node = rt->gateway.s_node;
                }

                /* Fix up skb->len field */
                skb_trim(skb, min(origlen, rt->dev->hard_header_len +
                        ddp_dl->header_length + ddphv.deh_len));

                /* Mend the byte order */
                *((__u16 *)ddp) = ntohs(*((__u16 *)&ddphv));

                /*
                 * Send the buffer onwards
                 *
                 * Now we must always be careful. If it's come from 
                 * LocalTalk to EtherTalk it might not fit
                 *
                 * Order matters here: If a packet has to be copied
                 * to make a new headroom (rare hopefully) then it
                 * won't need unsharing.
                 *
                 * Note. ddp-> becomes invalid at the realloc.
                 */
                if(skb_headroom(skb) < 22)
                        /* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
                        skb = skb_realloc_headroom(skb, 32);
                else
                        skb = skb_unshare(skb, GFP_ATOMIC);
                
                /*
                 * If the buffer didn't vanish into the lack of
                 * space bitbucket we can send it.
                 */
                if(skb)
                {
                        if(aarp_send_ddp(rt->dev, skb, &ta, NULL) == -1)
                                kfree_skb(skb);
                }

                return (0);
        }

#if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
        /*
         *      Check if IP-over-DDP
         */
        if(skb->data[12] == 22)
        {
                struct net_device *dev;

                /* This needs to be able to handle ipddp"N" devices */
                if((dev = __dev_get_by_name("ipddp0")) == NULL)
                        return (-ENODEV);

                skb->protocol = htons(ETH_P_IP);
                skb_pull(skb, 13);
                skb->dev = dev;
                skb->h.raw = skb->data;

                ((struct net_device_stats *)dev->priv)->rx_packets++;
                ((struct net_device_stats *)dev->priv)->rx_bytes += skb->len+13;
                netif_rx(skb);  /* Send the SKB up to a higher place. */

                return (0);
        }
#endif

        /*
         * Which socket - atalk_search_socket() looks for a *full match*
         * of the <net,node,port> tuple.
         */
        tosat.sat_addr.s_net  = ddp->deh_dnet;
        tosat.sat_addr.s_node = ddp->deh_dnode;
        tosat.sat_port = ddp->deh_dport;

        sock = atalk_search_socket(&tosat, atif);
        
        if(sock == NULL)        /* But not one of our sockets */
        {
                kfree_skb(skb);
                return (0);
        }

        /*
         *      Queue packet (standard)
         */
         
        skb->sk = sock;

        if(sock_queue_rcv_skb(sock, skb) < 0)
                kfree_skb(skb);

        return (0);
}

/*
 * Receive a LocalTalk frame. We make some demands on the caller here.
 * Caller must provide enough headroom on the packet to pull the short
 * header and append a long one.
 */
static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
{
        struct ddpehdr *ddp;
        struct at_addr *ap;

        /*
         * Expand any short form frames.
         */
        if(skb->mac.raw[2] == 1)
        {
                /*
                 * Find our address.
                 */

                ap = atalk_find_dev_addr(dev);
                if(ap == NULL || skb->len < sizeof(struct ddpshdr))
                {
                        kfree_skb(skb);
                        return (0);
                }

                /*
                 * The push leaves us with a ddephdr not an shdr, and
                 * handily the port bytes in the right place preset.
                 */

                skb_push(skb, sizeof(*ddp) - 4);
                ddp = (struct ddpehdr *)skb->data;

                /*
                 * Now fill in the long header.
                 */

                /*
                 * These two first. The mac overlays the new source/dest
                 * network information so we MUST copy these before
                 * we write the network numbers !
                 */

                ddp->deh_dnode = skb->mac.raw[0];     /* From physical header */
                ddp->deh_snode = skb->mac.raw[1];     /* From physical header */

                ddp->deh_dnet  = ap->s_net;     /* Network number */
                ddp->deh_snet  = ap->s_net;
                ddp->deh_sum   = 0;             /* No checksum */
                /*
                 * Not sure about this bit...
                 */
                ddp->deh_len   = skb->len;
                ddp->deh_hops  = DDP_MAXHOPS;   /* Non routable, so force a drop
                                                   if we slip up later */

                /* Mend the byte order */
                *((__u16 *)ddp) = htons(*((__u16 *)ddp));
        }
        skb->h.raw = skb->data;

        return (atalk_rcv(skb, dev, pt));
}

static int atalk_sendmsg(struct socket *sock, struct msghdr *msg, int len,
        struct scm_cookie *scm)
{
        struct sock *sk=sock->sk;
        struct sockaddr_at *usat=(struct sockaddr_at *)msg->msg_name;
        struct sockaddr_at local_satalk, gsat;
        struct sk_buff *skb;
        struct net_device *dev;
        struct ddpehdr *ddp;
        int size;
        struct atalk_route *rt;
        int loopback=0;
        int err;
        int flags = msg->msg_flags;

        if(flags & ~MSG_DONTWAIT)
                return (-EINVAL);

        if(len > DDP_MAXSZ)
                return (-EMSGSIZE);

        if(usat)
        {
                if(sk->zapped)
                {
                        if(atalk_autobind(sk) < 0)
                                return (-EBUSY);
                }

                if(msg->msg_namelen < sizeof(*usat))
                        return (-EINVAL);
                if(usat->sat_family != AF_APPLETALK)
                        return (-EINVAL);

                /* netatalk doesn't implement this check */
                if(usat->sat_addr.s_node == ATADDR_BCAST && !sk->broadcast)
                {
                        printk(KERN_INFO "SO_BROADCAST: Fix your netatalk as it will break before 2.2\n");
#if 0
                        return (-EPERM);
#endif
                }
        }
        else
        {
                if(sk->state != TCP_ESTABLISHED)
                        return (-ENOTCONN);
                usat =& local_satalk;
                usat->sat_family = AF_APPLETALK;
                usat->sat_port   = sk->protinfo.af_at.dest_port;
                usat->sat_addr.s_node = sk->protinfo.af_at.dest_node;
                usat->sat_addr.s_net  = sk->protinfo.af_at.dest_net;
        }

        /* Build a packet */

        SOCK_DEBUG(sk, "SK %p: Got address.\n",sk);

        /* For headers */
        size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;

        if(usat->sat_addr.s_net != 0 || usat->sat_addr.s_node == ATADDR_ANYNODE)
        {
                rt = atrtr_find(&usat->sat_addr);
                if(rt == NULL)
                        return (-ENETUNREACH);
                dev = rt->dev;
        }
        else
        {
                struct at_addr at_hint;
                at_hint.s_node = 0;
                at_hint.s_net  = sk->protinfo.af_at.src_net;
                rt = atrtr_find(&at_hint);
                if(rt == NULL)
                        return (-ENETUNREACH);
                dev = rt->dev;
        }

        SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n", sk, size, dev->name);

        size += dev->hard_header_len;

        skb = sock_alloc_send_skb(sk, size, 0, flags&MSG_DONTWAIT, &err);
        if(skb == NULL)
                return (err);
        
        skb->sk = sk;
        skb_reserve(skb, ddp_dl->header_length);
        skb_reserve(skb, dev->hard_header_len);

        skb->dev = dev;

        SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);

        ddp = (struct ddpehdr *)skb_put(skb,sizeof(struct ddpehdr));
        ddp->deh_pad  = 0;
        ddp->deh_hops = 0;
        ddp->deh_len  = len + sizeof(*ddp);
        /*
         * Fix up the length field [Ok this is horrible but otherwise
         * I end up with unions of bit fields and messy bit field order
         * compiler/endian dependencies..
         */
        *((__u16 *)ddp) = ntohs(*((__u16 *)ddp));

        ddp->deh_dnet  = usat->sat_addr.s_net;
        ddp->deh_snet  = sk->protinfo.af_at.src_net;
        ddp->deh_dnode = usat->sat_addr.s_node;
        ddp->deh_snode = sk->protinfo.af_at.src_node;
        ddp->deh_dport = usat->sat_port;
        ddp->deh_sport = sk->protinfo.af_at.src_port;

        SOCK_DEBUG(sk, "SK %p: Copy user data (%d bytes).\n", sk, len);

        err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
        if(err)
        {
                kfree_skb(skb);
                return (-EFAULT);
        }

        if(sk->no_check == 1)
                ddp->deh_sum = 0;
        else
                ddp->deh_sum = atalk_checksum(ddp, len + sizeof(*ddp));

        /*
         * Loopback broadcast packets to non gateway targets (ie routes
         * to group we are in)
         */
        if(ddp->deh_dnode == ATADDR_BCAST)
        {
                if((!(rt->flags&RTF_GATEWAY)) && (!(dev->flags&IFF_LOOPBACK)))
                {
                        struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);
                        if(skb2)
                        {
                                loopback = 1;
                                SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
                                if(aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL) == -1)
                                        kfree_skb(skb2);
                                /* else queued/sent above in the aarp queue */
                        }
                }
        }

        if((dev->flags & IFF_LOOPBACK) || loopback)
        {
                SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
                /* loop back */
                skb_orphan(skb);
                ddp_dl->datalink_header(ddp_dl, skb, dev->dev_addr);
                skb->mac.raw = skb->data;
                skb->h.raw   = skb->data + ddp_dl->header_length + dev->hard_header_len;
                skb_pull(skb,dev->hard_header_len);
                skb_pull(skb,ddp_dl->header_length);
                atalk_rcv(skb, dev, NULL);
        }
        else
        {
                SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
                if (rt->flags & RTF_GATEWAY)
                {
                    gsat.sat_addr = rt->gateway;
                    usat = &gsat;
                }

                if(aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
                        kfree_skb(skb);
                /* else queued/sent above in the aarp queue */
        }
        SOCK_DEBUG(sk, "SK %p: Done write (%d).\n", sk, len);

        return (len);
}

static int atalk_recvmsg(struct socket *sock, struct msghdr *msg, int size,
                int flags, struct scm_cookie *scm)
{
        struct sock *sk=sock->sk;
        struct sockaddr_at *sat=(struct sockaddr_at *)msg->msg_name;
        struct ddpehdr  *ddp = NULL;
        struct ddpebits ddphv;
        int copied = 0;
        struct sk_buff *skb;
        int err = 0;


        skb = skb_recv_datagram(sk,flags&~MSG_DONTWAIT,flags&MSG_DONTWAIT,&err);
        if(skb == NULL)
                return (err);

        ddp = (struct ddpehdr *)(skb->h.raw);
        *((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));

        if(sk->type == SOCK_RAW)
        {
                copied = ddphv.deh_len;
                if(copied > size)
                {
                        copied = size;
                        msg->msg_flags |= MSG_TRUNC;
                }

                err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
        }
        else
        {
                copied = ddphv.deh_len - sizeof(*ddp);
                if(copied > size)
                {
                        copied = size;
                        msg->msg_flags |= MSG_TRUNC;
                }
                err = skb_copy_datagram_iovec(skb,sizeof(*ddp),msg->msg_iov,copied);
        }

        if(!err)
        {
                if(sat)
                {
                        sat->sat_family      = AF_APPLETALK;
                        sat->sat_port        = ddp->deh_sport;
                        sat->sat_addr.s_node = ddp->deh_snode;
                        sat->sat_addr.s_net  = ddp->deh_snet;
                }
                msg->msg_namelen = sizeof(*sat);
        }

        skb_free_datagram(sk, skb);     /* Free the datagram. */

        return (err ? err : (copied));
}


/*
 * AppleTalk ioctl calls.
 */
static int atalk_ioctl(struct socket *sock,unsigned int cmd, unsigned long arg)
{
        long amount=0;
        struct sock *sk=sock->sk;

        switch(cmd)
        {
                /*
                 *      Protocol layer
                 */
                case TIOCOUTQ:
                        amount = sk->sndbuf - atomic_read(&sk->wmem_alloc);
                        if(amount < 0)
                                amount = 0;
                        break;

                case TIOCINQ:
                {
                        struct sk_buff *skb;
                        /* These two are safe on a single CPU system as only user tasks fiddle here */
                        if((skb = skb_peek(&sk->receive_queue)) != NULL)
                                amount = skb->len-sizeof(struct ddpehdr);
                        break;
                }

                case SIOCGSTAMP:
                        if(sk)
                        {
                                if(sk->stamp.tv_sec == 0)
                                        return -ENOENT;
                                return (copy_to_user((void *)arg,&sk->stamp,sizeof(struct timeval)) ? -EFAULT : 0);
                        }
                        return (-EINVAL);

                /*
                 * Routing
                 */
                case SIOCADDRT:
                case SIOCDELRT:
                        if(!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        return (atrtr_ioctl(cmd,(void *)arg));

                /*
                 * Interface
                 */
                case SIOCGIFADDR:
                case SIOCSIFADDR:
                case SIOCGIFBRDADDR:
                case SIOCATALKDIFADDR:
                case SIOCDIFADDR:
                case SIOCSARP:  /* proxy AARP */
                case SIOCDARP:  /* proxy AARP */
                        return (atif_ioctl(cmd,(void *)arg));

                /*
                 * Physical layer ioctl calls
                 */
                case SIOCSIFLINK:
                case SIOCGIFHWADDR:
                case SIOCSIFHWADDR:
                case SIOCGIFFLAGS:
                case SIOCSIFFLAGS:
                case SIOCGIFMTU:
                case SIOCGIFCONF:
                case SIOCADDMULTI:
                case SIOCDELMULTI:
                case SIOCGIFCOUNT:
                case SIOCGIFINDEX:
                case SIOCGIFNAME:
                        return ((dev_ioctl(cmd,(void *) arg)));

                case SIOCSIFMETRIC:
                case SIOCSIFBRDADDR:
                case SIOCGIFNETMASK:
                case SIOCSIFNETMASK:
                case SIOCGIFMEM:
                case SIOCSIFMEM:
                case SIOCGIFDSTADDR:
                case SIOCSIFDSTADDR:
                        return (-EINVAL);

                default:
                        return (-EINVAL);
        }

        return (put_user(amount, (int *)arg));
}

static struct net_proto_family atalk_family_ops=
{
        PF_APPLETALK,
        atalk_create
};

static struct proto_ops SOCKOPS_WRAPPED(atalk_dgram_ops)=
{
        PF_APPLETALK,

        atalk_release,
        atalk_bind,
        atalk_connect,
        sock_no_socketpair,
        sock_no_accept,
        atalk_getname,
        datagram_poll,
        atalk_ioctl,
        sock_no_listen,
        sock_no_shutdown,
        sock_no_setsockopt,
        sock_no_getsockopt,
        sock_no_fcntl,
        atalk_sendmsg,
        atalk_recvmsg,
        sock_no_mmap
};

#include <linux/smp_lock.h>
SOCKOPS_WRAP(atalk_dgram, PF_APPLETALK);

static struct notifier_block ddp_notifier=
{
        ddp_device_event,
        NULL,
        0
};

struct packet_type ltalk_packet_type=
{
        0,
        NULL,
        ltalk_rcv,
        NULL,
        NULL
};

struct packet_type ppptalk_packet_type=
{
        0,
        NULL,
        atalk_rcv,
        NULL,
        NULL
};

static char ddp_snap_id[] = {0x08, 0x00, 0x07, 0x80, 0x9B};

/*
 * Export symbols for use by drivers when AppleTalk is a module.
 */
EXPORT_SYMBOL(aarp_send_ddp);
EXPORT_SYMBOL(atrtr_get_dev);
EXPORT_SYMBOL(atalk_find_dev_addr);

/* Called by proto.c on kernel start up */

void __init atalk_proto_init(struct net_proto *pro)
{
        (void) sock_register(&atalk_family_ops);
        if((ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv)) == NULL)
                printk(KERN_CRIT "Unable to register DDP with SNAP.\n");

        ltalk_packet_type.type = htons(ETH_P_LOCALTALK);
        dev_add_pack(&ltalk_packet_type);

        ppptalk_packet_type.type = htons(ETH_P_PPPTALK);
        dev_add_pack(&ppptalk_packet_type);

        register_netdevice_notifier(&ddp_notifier);
        aarp_proto_init();

#ifdef CONFIG_PROC_FS
        proc_net_create("appletalk", 0, atalk_get_info);
        proc_net_create("atalk_route", 0, atalk_rt_get_info);
        proc_net_create("atalk_iface", 0, atalk_if_get_info);

        aarp_register_proc_fs();
#endif /* CONFIG_PROC_FS */

#ifdef CONFIG_SYSCTL
        atalk_register_sysctl();
#endif /* CONFIG_SYSCTL */

        printk(KERN_INFO "NET4: AppleTalk 0.18 for Linux NET4.0\n");
}

#ifdef MODULE

int init_module(void)
{
        atalk_proto_init(NULL);
        return (0);
}

/*
 * Note on MOD_{INC,DEC}_USE_COUNT:
 *
 * Use counts are incremented/decremented when
 * sockets are created/deleted.
 *
 * AppleTalk interfaces are not incremented untill atalkd is run
 * and are only decremented when they are downed.
 *
 * Ergo, before the AppleTalk module can be removed, all AppleTalk
 * sockets be closed from user space.
 */

void cleanup_module(void)
{
#ifdef CONFIG_SYSCTL
        atalk_unregister_sysctl();
#endif /* CONFIG_SYSCTL */

#ifdef CONFIG_PROC_FS
        proc_net_remove("appletalk");
        proc_net_remove("atalk_route");
        proc_net_remove("atalk_iface");

        aarp_unregister_proc_fs();
#endif /* CONFIG_PROC_FS */

        aarp_cleanup_module();  /* General aarp clean-up. */

        unregister_netdevice_notifier(&ddp_notifier);
        dev_remove_pack(&ltalk_packet_type);
        dev_remove_pack(&ppptalk_packet_type);
        unregister_snap_client(ddp_snap_id);
        sock_unregister(PF_APPLETALK);

        return;
}

#endif  /* MODULE */
#endif  /* CONFIG_ATALK || CONFIG_ATALK_MODULE */